The "EPR" refers to the 1935 Einstein-Podolsky-Rosen thought experiment in which two particle systems interact with each other in a very particular way and are then separated. Position (let's say) is measured in one system, which then determines position in the other; momentum may then be measured in the second system, violating the uncertainty principle.

This entaglement (or "spukhafte Fernwirkung" or "spooky action at a distance" as Einstein called it) has since been proven in experiments.

It therefore follows (sfnally) that communication should be possible in such a way that it cannot possibly be intercepted (look for Sprint's "Spooky Service at a Distance" available soon!).